IKO Perforated slate Sand surface underlay is a venting underlay consisting of a strong glass fibre base coated with oxidised bitumen. It is sand finished on both surfaces. The perforations are nominally 25mm in diameter, positioned at approximately 75mm to 85mm apart throughout the roll. IKO Perforated Sand Underlay is sometimes used (loose laid) to provide a controlled partial bond to a substrate, when the subsequent layer is fully bonded in hot bitumen, in a built-up roofing system.

Key Features

Glass fibre based

Economic

BS 747 2000 Type 3 Bitumen Roofing Membranes

ApplicationGlass fibre based membranes should be installed in accordance with BS 8217: 2005, Code of practice for reinforced bitumen membranes for roofing, and to IKO specifications. Glass fibre based roofing membranes are applied by traditional our & roll methods. Hot bitumen is poured in front of the roofing felt roll, which is then unrolled into the bitumen, spreading t to give a continuous coating for the full width. The membranes are applied with minimum 75mm side and end laps.

Built-up roofing alternativesGlass fibre based membranes are typically installed in two and three layer systems. In a two-layer system both layers should be fully bonded, the underlay being bonded to a suitable insulation or substrate. In a three-layer system the cap sheet and intermediate layers should be fully bonded to a random nailed preparation layer or to IKO Perforated Slate Underlay, depending on the substrate or insulation specified. Detailed specification advice is available from the IKO Technical & Design Services Department.